The present invention relates to saws for cutting concrete and, more particularly, to saws for cutting green concrete. Green concrete, as used herein, is concrete less than approximately 36 hours after pouring.
Large concrete slabs are prone to cracking as a result of contraction as they cure. Uncontrolled, such cracks may form anywhere within the concrete slab.
One method of controlling the formation and location of cracks in the slab is to provide grooves in the concrete before the concrete is fully set. Since the slab is weakest along the cross sectional plane defined by the groove, if the groove is deep enough relative to the thickness of the concrete slab, potential stress cracks in the curing concrete slab will form along the grooves rather than randomly in ungrooved expanses of the concrete slab. After the concrete is completely cured, stress cracks which form along the predefined grooves in the concrete can be filled with a suitable filler.
Several methods and devices are known for creating such stress-cracks in concrete slabs. One method is to form grooves with a hand held tool, such as a trowel, while the concrete is soft enough to be worked by hand. Another method is to use a saw to cut grooves before the concrete is set.
One type of saw to cut grooves in concrete is disclosed in U.S. Pat. No. 5,056,499. This patent discloses a concrete cutting saw having a slotted skid plate through which a circular saw plate projects to cut the concrete. One disadvantage of concrete saws of the type disclosed in this above patent in that the maximum depth of cut is in the range of one and one-quarter to one and three-quarters inches in depth. Shallow cuts such as these are often not sufficient for providing stress planes in thick concrete slabs. The limitation in the depth of cut in devices such as those in the above-referenced patent is due to the requirement for relatively light weight, and thus low power, so that the saw does not unduly mark the surface of the green concrete. Another disadvantage is, that despite its light weight, it can still mark the surface of green concrete as the skid plate is pushed over the concrete surface even when cutting green concrete.
In view of the foregoing, it is a principal object of the present invention to provide a concrete cutting saw that can cut green or uncured concrete and which has the power and weight to cut to a depth of at least three inches, but will not unduly mark the surface of green or uncured concrete.
Another object of the present invention is to provide a green or uncured concrete cutting saw which will maintain the integrity of the-surface of the concrete being cut.
Another object of the present invention is to provide a concrete cutting saw for green or cured concrete, or bituminous concrete, which can drive itself along the surface of the concrete at a desired preselected speed while cutting the concrete at a desired depth, without marring the surface of green concrete.
A still further object of the present invention is to provide a green or uncured concrete cutting saw having continuous smooth tracks which roll over the concrete adjacent each side of the saw blade to support the surface and more importantly stabilize the saw to prevent vibration and subsequent raveling of the concrete adjacent the cut.
Additional objects and advantages of the present invention and the novel features and details thereof will become apparent to those skilled in the art from the detailed description of the invention.